In DC, how many examples of villains fighting different heroes are there?

[GilGarciaJr]

I always thought it was wild when they retcon Mordru, primarily known as a villain to the Legion of Superheroes in the 30th century, as also being a recurring nemesis to the JSA in the 21st century in his younger days, and to Dr. Fate in particular

[Zero Hunter]

Yeah it makes sense that villains with Global Plans (Ras Al Ghul, Vandal Savage) should run into multiple heroes.

They even had Ra's Al Ghul show up in the 31st century to fight the Legion. The crazy thing is his plan was much more epic than anything he has done in the modern day, and it almost worked. It is always cool when the Legion uses modern villains because they can use them on such a bigger scale than they can in the modern day. When they used Darkseid they had taking over and entire planet and using the Daxmites as his army. I would love to see characters like Vandal Savage, Eclipso, Deparo, ect used in the Legion time just to see them really cut lose.

[Tec15]

In addition to all those mentioned above:

-King Shark started out as a Superboy villain, but has become more associated with the Secret Six and Suicide Squad (He'll even be appearing in the Suicide Squad sequel and only just missed out on appearing in the first one). He's also become more of an Aquaman supporting character/villain in the meantime, and is thought of as an Aquaman villian now, if he's thought of as anyone's villain at all.

-On that note, Green Lantern villain the Shark, has also fought Aquaman numerous times, but his star and niche (Shark-man) has well and truly been stolen by King Shark and he's pretty much a minor character now.

-Jason Woodrue (The Floronic Man, Seeder) started out as an Atom villain, fought Green Lantern in his first plant-man form appearance, then menaced the Justice League as part of a team (Injustice League, Secret Society). Then Alan Moore used him in his Swamp Thing run and he's pretty much thought of as Swamp Thing villain now, even appearing in his latest TV show. In the meantime, he was also retconned into having a connection in Poison Ivy's origin, even appearing in this capacity in the movie 'Batman & Robin'.

-Kobra started out as villain protagonist with his own book. After it's cancellation he became a general DC universe villain and fought against pretty much anyone and everyone. Including Batman, Aquaman, Superman, Wonder Woman, The Outsiders, Flash (Wally West version), Suicide Squad, Checkmate and the JSA. He makes a good villain whenever the script calls for a generic terrorist organization.

That's just of the top of my head. I'm sure there's even more examples out there.

[Hybrid]

Lady Shiva was created to be the archenemy of Richard Dragon, but eventually went on to menace Batman, the Birds of Prey, Robin (Tim Drake), and of course, her daughter Cassandra Cain.